Steam engine with cam actuated valves



Sept. 28,1954 R. L. HARRIS ETAL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheeis-Sheet 1 v I F'io/ M I F16. I 20(- I I 35 I 25 42 w M a]. I 3 r" 4 J a j IN V EN TOR! iviiir z, #4024 M40: 4071/! p in W Sept. 28, 1954 R. 1.. HARRIS HAL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 2 Irma/vi) Sept. 28, 1954 s ETAL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 3 I N V EN TOR! Fail 1, HlFP/f M49505 407%?09 lrram/n Sept. 28, 1954 R. HARRIS ET AL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 4 IN V EN TOR5 Fail-I7 4, M44 94! M40605 4 d 777 6 0? Sept. 28, 1954 R. HARRIS ET AL STEAM ENGINE WITH CAM ACTUATED VALVES 9 Sheets-Sheet 5 Filed March 28, 1952 INVENTOR! 4 05197 L, #44 05 Y paw: wa e: @222 /ipg/ irraI/vi/ pa. I31

Sept. 28, 1954 R. 1.. HARRIS ET AL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 6 INVENTOR! payer 4/1494: M4460! or/man Sept. 28, 1954 v HARRls ETAL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 7 JNVENTOR5 Payer AJMii/i Miiifl! 4077494 Sept. 28, 1954 HARRIS ETAL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 8 45 717 25/ 1;: 759 4a 2;: \W. A? w 259 772 75/ iii [6 (22 7. U Vi FIG. /7

INVENTORS Arrae/w-Y Sept. 28, 1954 R. HARRIS ETAL 2,690,165

STEAM ENGINE WITH CAM ACTUATED VALVES Filed March 28, 1952 9 Sheets-Sheet 9 FIG. /8

IN V EN TOR5 205E4 7" 41/4994; M4960: Lon/pap imam i) Patented Sept. 28, 1954 STATES STEAM ENGINE WITH CAM AGTUATED VALVES Robert L. Harris and Marcus Lothrop, Berkeley,

Calif., assignors to Yuba Manufacturing Company, a corporation 14 Claims. 1

Our invention relates to engines operated by fluids and is especially concerned with engines primarily for vehicular use and of the type shown in our co-pending application, Serial Number 52,662, filed October 9, 1948, and entitled Steam Engine Having a Unitary Valve Actuator, now Patent No. 2,591,933, issued April 8, 1952.

One of the types of reciprocating, fluid-actuated engines employs unbalanced poppet valves in the cylinders to control the admission and release of operating fluid. For vehicular engine use it is customary to provide a forward motion valve actuation, a rearward motion valve actuation, and almost always several positions of steam cutoif of the inlet valve. Presently used steam temperatures and pressures are moderately high, usually approximating 1000 degrees Fahrenheit and 2000 pounds per square inch. It is desirable to operate a reciprocating steam engine at a relatively high speed, say, 2500 revolutions per minute. All of these factors make it difficult to provide satisfactory valve motion. It is difficult to shift the valve actuating structure from forward to reverse position. It is difiicult to change the inlet cutoff positions. It is even more difficult to accomplish these changes at high speed and at high temperatures and high pressures. It has been found hard in actual practice to keep wear to a reasonable amount. Some of the wear is apparently due to high loads and some of it is apparently due to unsatisfactory lubrication.

It is therefore an object of our invention to provide an improved steam engine with cam actuated valves.

Another object of our invention is to provide a valve mechanism for a steam engine which can easily be shifted into various different operating positions.

A further object of our invention is to provide a steam engine with adequate lubrication.

A still further object of our invention is to provide a steam engine valve mechanism capable of long life under severe operating conditions, i. e. high pressure, high temperature and high speed.

An additional object of our invention is to provide an engine with cam actuated valves which can readily be fabricated without costly machining and by ordinary techniques.

Other objects, together with the foregoing, are attained in the embodiments of the engine described in the accompanying description and illustrated in the accompanying drawings, in which:

Figure 1 is a cross section through an engine constructed in accordance with our invention,

many of the parts being shown in side elevation and some portions being broken away to disclose the interior construction and to reduce the size of the figure.

Figure 2 is a cross section of an engine constructed in accordance with our invention, the principal planes of section being indicated by the lines .22 of Figure 1 and the scale being reduced. Certain parts are shown in difierent planes of section and other portions are removed for clarity of disclosure.

Figure 3 is a cross section, the plane of which is indicated by the line 3-3 of Figure 1.

Figure 4 is a cross section, the several planes of which are indicated by the lines 4 d of Figure 3.

Figure 5 is a detail in cross section, the plane of which is indicated by the line 5-5 of Figure 4.

Figure 6 is a side elevation with portions in section, the general planes of the view being indicated by the line 66 of Figure 3.

Figure 7 is a fragmentary view showing in plan a portion of the exhaust cam mechanism in reverse position.

Figure 8 is a fragmentary view showing in plan a portion of the exhaust cam mechanism in forward position.

Figure 9 is a fragmentary plan showing an inlet cam in reverse position.

Figure 10 is a fragmentary plan showing the inlet cam of Figure 9 in 10% cutoff forward position.

Figure 11 is a fragmentary plan showing an inlet cam for 40% cutoff forward position.

Figure 12 is a fragmentary plan showing an inlet cam for cutoff forward position.

Figure 13 shows in fragmentary plan in views A, B, C and D the several positions of the exhaust cam for the four operating conditions of the engine.

Figure 14 shows in fragmentary plan in views A, B, C and D the four positions of one of the inlet cams for the four conditions of the engine.

Figure 15 shows in fragmentary plan in its four views A, B, C and D the positions of another inlet cam for the four conditions of the engine.

Figure 16 shows in fragmentary plan in its four views A, B, C and D the positions of an additional inlet cam for the four conditions of the engine.

Figure 17 is a View somewhat like Figure 3 showing a modified form of engine cam mechanism partially in plan and partially in cross section on a transverse plane.

Figure 18 is a cross section, parts being in side elevation, of the modified form of structure 11- lustrated in Figure 17, the various planes of sec- 3 tion being indicated by the lines iii-l3 of Figure 17.

In the practical embodiment of the invention as illustrated in Figures 1 to 16, there is provided an engine assembly having a generally rectangular crank case 6 carrying bearings l and 8 to mount a crank shaft 8 with its axis substantially vertical. Arranged. on either side of the crank shaft are pairs of cylinders iii and H as well as I2 and i3. Within each of the cylinders is a piston i i connected by a suitable connecting rod l5 to its respective portion of the crank shaft 8.

As especially shown in Figure 2, each of the cylinders is provided with an inlet poppet valve l6 designed to control the influx of operating fluid, such as steam, to the engine. The valve [6 has a stem ll arranged with its axis in one plane parallel to the axis of the crank shaft and also in another plane perpendicular to the axis of the crank shaft.

The valve is closed by a spring is in the customary fashion and is operated by reciprocation in the direction of its axis. Somewhat similarly, the cylinder is provided with an exhaust valve 2i having a stem 22 the axis of which is substantially coincident with that of the cylinder, is parallel to the axis of the valve i6 and is in a plane perpendicular to the axis of the crank shaft. The valve stem 22 emerges from the head of the cylinder and carries a return spring 23 in the usual way. Operation of the exhaust valve in the direction of its axis controls the outflow of steam from the cylinder.

There is provided mechanism for operating the various valves in the various cylinders not only in proper sequence or time but also at several selected times in accordance with the desires of the operator. The crank shaft 9 adjacent its upper end is provided with a cam assembly 26 (Figures 1 and l). The cam assembly is made up of a number of individual cam rings and is also inclusive of a. bottom plate 2'! and a top plate 28, both provided with connecting keys 29 and 30 for securing the cam assembly for rota- U tion in unison with the engine crank shaft. The plates are held in proper relationship by spacer bolts 32 and 33 disposed on a diameter of the cam assembly.

Located on the bolts 32 and 33 between the top and bottom plates 21 and 28 is an intermediate ring 34 (Figures 4 and 5). This is mounted in correct axial position by threaded engagement with the bolts 32 and 33 and is locked by appropriate set screws 35. The outlines or envelope contours of the ring 34 and of the plates 21 and 28 are largely but not entirely circular and their peripheries serve in part as positioning surfaces for the cam mechanism.

Since there are four cylinders there are provided four substantially identical valve actuating devices, the description of one applying generally to the others. As an example, there is provided for the cylinder if! an appropriate cam follower 36 (Figures 1, 3 and 4) constituted by a lever having a broad axially extending shoe 3! of sufficient extent to overlap the edge of the plate 28 and part of the ring 34. The lever or follower is also provided with a hub 38 oscillatable on a pin 39 anchored in the top bearing wall 4i (Figure 1) and in the cover wall t? of the crank case. As the follower 36 oscillates about the axis of the pin 39, the shoe 3'! moves with a substantial radial component with respect to the crank shaft axis.

In abutment with a contact boss 43 on the follower 36 is a similar contact boss 44 on a rocker 46. The rocker 46 includes a hub ll rotatable about a pin 48 appropriately mounted in the crank case 6. Also included in the rocker 46 is an adjustable ball end 49 socketed in the cooperating end of a push rod 51 extending through an appropriate opening 50 in the crank case wall 4|. The lower end of the push rod 5! (Figure 1) extends to an appropriate seat in an arm 52 of a bell crank 53. The hub of the bell crank is journaled for oscillation on a stub shaft 54 removably anchored between an outer wall 56 (Figure 2) of the crank case and an inner bracket wall 51 therein. The push rod axis is not exactly parallel to the axis of the crank shaft but is in the same general direction and can be characterized as approximately or substantially parallel to the crank shaft.

Extending into the crankcase with its axis in a plane approximately perpendicular to the axis of the crankshaft is a thrust rod 59, one end of which is received in a socket 58 on the bell crank 53. The thrust rod 59 passes through a tube 6| included in the cylinder casting and emerges at the cylinder head to engage a socket 62 at one end of a rocker lever 63, a symmetrical and corresponding lever being shown in full lines in the upper left hand portion of Figure 2. The rocker lever 63 is journaled on a central pin 68 secured in a bracket 61 fastened to the cylinder casting. The bracket also carries a bolt 6% for holding a cover 69 in position. The other end of the rocker lever 63 has an enlarged boss H in abutment with the end of the valve stem 22. With this motion train, any movement of the follower 36 and of the shoe 3'! in a radial direction causes oscillation of the rocker 46, a longitudinal motion of the push rod 5|, a rotary oscillation of the bell crank 53 and a corresponding longitudinal motion of the thrust rod 59. This is productive of a rocking motion of the rocker lever 63 and a corresponding translation of the valve stem 22 and actuation of the exhaust valve.

In a comparable fashion for each of the cylinders an inlet valve actuating mechanism is provided. This includes a follower 75 (Figures 4 and 6) having a hub 16 also journaled on the pin 39 and carrying an axially extended shoe ll effective to span in an axial direction from the ring 34 to the lower plate 21. The follower i5 also has an extension 18 abutting a pad '19 on a rocker crank 8|. This crank includes a relatively long hub journaled on a pin 82 parallel to the pin 48 and similarly mounted. Extending from the hub of the crank BI is an arm 83 carrying an adjustable ball mechanism 84 received in the socketed end of a push rod 86. The push rod also extends through the opening 50 in the wall 41 of the crank case and at its lower end is received in a bell crank 81 (Figure 2) also journaled on the stub shaft 54. The axis of the push rod 86 is inclined somewhat more to the axis of the crankshaft than is that of the push rod 5|, but still can be characterized as being substantially parallel to the crankshaft. Motion of the bell crank 81! is imparted to the adjacent inlet valve by an arm 88 depending from the bell crank ti and in immediate contact with the inlet valve stem l1 itself.

With this motion train, when the follower shoe TI is given a rotary motion having a radial component, the rocker crank 8| is oscillated and the push rod 86 is similarly moved in a longitudinal direction. The bell crank 81 is rotated on its shaft 54 and the stem I! of the associated inlet valve is operated. Substantially identical actuating mechanisms are provided at four equally spaced points around the periphery of the cam assembly 26 and by appropriate pairs of push rods, like the push rods BI and 86, the motion is trans mitted'in proper sequence to the various cylinders of the engine. The push rods are of. different lengths and are of diiferent inclinations because of the geometry of the engine layout but-all of them are characterized as having their axes substantially or approximately parallel to that of the crank shaft. While this valve motion train is inclusive of a large number of different parts and is in some respects somewhat more massive than is desirable for high speed operation, yet it provides a relatively rigid or stiff system. Despite the number of elements involved in the valve motion train movements imparted to the shoes 3? and 17 are transmitted without substantial variation or change to the stem I! of the inlet valve and to the stem 22 of the exhaustvalve. The motion train is susceptible of operation at relatively high speed and under high pressures without substantial error in the valve action.

The particular time at which the followers 35 and I5 are operated with respect to the rotary position of the crankshaft determines whether or not the engine will run forward or backward. The particular duration of movement of the inlet follower I5 determines whether the steam admitted to the cylinder adjacent top dead center position of the piston will be cut off near the end of the inlet stroke, near the middle of the inlet stroke, or near the beginning of the inlet stroke. To provide the various valve events desired, the cam assembly 26 is not entirely a fixed or rigid mechanism although the bottom plate 2l,the top plate 28 and the intermediate ring 34 are held by the bolts 32 and 33 in fixed relationship to the crank shaft. Other parts of the cam assembly are movable. v

As shown particularly in Figures '7 and 8, for example, there is provided an exhaust cam IIlI which is essentially a ring journaled to oscillate or swing about the bolt 32 as a hub from one extreme position as shown in Figure 7 to an opposite extreme position as shown in Figure 8. The cam ring IIlI is provided with an elongated arcuate slot I02 so that the movement can take place without interference with the bolt.33. In the cam ring position shown in Figure '7, it being understood that the direction of engine rotation is counterclockwise as shown by the arrow I03, upon rotation of the cam assembly with the crankshaft the exhaust follower shoe 31 is first actuated in a valve opening direction by ramp surfaces I04 and dwell surfaces I06 formed on both the upper plate 28 and the adjacent portion of the intermediate ring 34. The force for opening the valve is imposed on the shoe by these two spaced and fixed members of the cam assembly.

The contour of the dwell surface N16 is conpistons in the associated cylinders and to close I tion operates the exhaust valves properly within the time limits for reverse engine rotation.

tinued by an exactly coincident dwell surface Ill? on the cam ring IIlI. This dwell surface in the stated position of the cam is concentric with the axis of the crankshaft. The surface Ill'I terminates in a ramp I08 leading to the base circle configuration IIJ9 of the plate 28 and the ring 34. In effect, therefore, in this position of the cam ring IIII, the projected or envelope curvature of the cam ring, of the plate 28 and of a portion of the intermediate ring 34 is a cam contour effective to open the exhaust valves approximately 45 degrees before bottom dead center position of the When the cam IIII is shifted from its reverse position at one extreme as shown in Figure 7 to its forward position at its other extreme as shown in Figure 8, the surface I01 and the ramp I08 are both completely withdrawn within the envelope curvature I09 of the top plate 28 and the intermediate ring 34. The contour III across the diameter of the cam is such that in the position shown in Figure 8 part of the cam is concentric with and continues the dwell surface I08. The cam contourI I I then merges with a ramp portion I I2 symmetrical with the ramp portion I08. The direction of engine rotation with the exhaust cam in this position is clockwise as indicated by the arrow H3 in Figure'8. When the cam IIII is projected on one side of a center plane the envelope curvature of the cam is proper for one direction or rotation of the engine with the other portions of the cam being withdrawn or'masked or made inoperative. With the cam projected to the opposite extreme position for the opposite direction of engine rotation, the previously masked or inoperative portions of the cam are projected for o eration and the previously operating portions of the cam are themselves masked. There is consequently provided by the combination of the top plate 28 the intermediate ring 34 and the shiftable intervening cam IIlI what amounts to a variable cam for the exhaust functions of reverse and forward motion.

In a somewhat similar fashion, there is provided, as especially shown in Figures 9 and 10, a cam ring I2I arranged to rotate about the bolt 32 as a hub and having an arcuate slot I22 to limit its motion about the bolt 33. This cam ring is designed to operate the inlet valves both in the reverse engine rotation and in the forward rotation with a short or early cutoff, approximately 10 per cent. The operation of the cam ring I2I is quite similar to that of the cam ring I0 I. When the direction of rotation is as shown by the arrow I23 in Figure 9, that is, in reverse, the cam is positioned so that all of its contour not taking part in the reversesequence is withdrawn. There is then a projecting portion I24 with appropriate ramps I26 and I2? and a concentric portion I28. The concentric portion registers in plan with corresponding portions of the intermediate ring 3 and of the lower plate 21. The resulting envelope contour with this direction of rotation lifts the inlet valves by cam actuation against the follower shoe II at top dead center position of the pistons in the cylinders and then closes the inlet valves at about 60 degrees before bottom dead center positions of the pistons in their cylinders.

When the cam ring I2I is swung to its opposite extreme position as shown in Figure 10, the direction of rotation is forward as shown by the arrow I29. The previously described cam surfaces are then withdrawn within the envelope curvature of the'intermediate ring and the bottom plate 21 but a short cutoff portion I3I with adjacent ramps I32 and I33 then projects. The remaining portion I34 is concentric. The angular extent of the cam portion I 3I is only sufficient to open the inlet valve at approximately top dead center position of the piston and then to close the valve again at a short cutofi approximately ten per cent of the stroke of the piston away from top dead center location. The cam ring I2I therefore in one extreme position is effective to control the inlet valves during reverse motion with a relatively long cutoff and in its other extreme position is effective to control the inlet valves for forward rotation but with short cutoff.

To supplement the operation of the cam ring I2I there is, as shown in Figure 11, another cam ring I36 included in the cam assembly. This cam ring is likewise freely rotatable about the bolt 32 and is provided with an arcuate slot I31 for clearance and limitation of motion with respect to the bolt 33. The cam ring I36 is so arranged that it has a portion I38 which never projects beyond the envelope boundary of the corresponding portion of the intermediate ring 34 or of the lower plate 21. On its opposite side, however, it is provided with an extended portion I39 and adjacent ramps MI and I42 as well as a concentric portion I43. This extreme position of the cam ring I36 is effective in forward rotation as shown by the arrow I44 in Figure 11 to actuate the inlet valves. Each valve is held open from approximately top dead center position of the piston to an intermediate cutoff position at approximately 40 per cent of the total piston stroke. Preferably, the cam rings I2I and I36 operate simultaneously in the 40 per cent stroke cutoff position so that the inlet follower shoe 11 is actuated by both cams for the opening motion but is finally permitted to close solely by the ramp I42 of the cam ring I36. In its opposite extreme position, the cam ring I36 is ineffective.

To provide the third forward inlet valve closing option at about '15 per cent of the piston stroke away from top dead center, there is supplied an additional cam ring I46 as shown in Figure 12. This cam ring is rotatable about the bolt 32 as a hub and. is also provided with a slot I41 giving clearance and affording a stop with regard to the bolt 33. The cam ring I46 is like the cam ring I36 in that it has an inactive periphery I48 around substantially half of its circumference. This never projects beyond the envelope boundary of the intermediate ring 34 or of the lower plate 21. The remaining portion of the cam ring I46 is provided with an extended dwell portion I49 and adjacent ramps II and I52. Thus, when the cam ring is swung into one extreme position, the surface I48 is ineffective because it never projects whereas in the opposite extreme position the dwell portion I49 is projected and the inlet valve is held open to about '15 per cent of the stroke of the corresponding piston. As indicated in Figure 12, the location of the various cam rings I2I, I36 and I46 is preferably such that for the forward opening of an inlet valve the shoe 11 is simultaneously engaged by all of the lifting ramps I32, I41, and I5I whereas the closure of the valve depends on the ramp last exposed, such as I52. With this mechanism, therefore, it is possible by suitably orienting the various earn rings to produce both exhaust and inlet functions for both reverse and forward movement and to provide a total of three different cutoff closures for the inlet valves in forward motion.

In order that the cam rings IOI, I2I, I36, and I46 can be projected to one side or the other in appropriate order, I provide an internal actuating member particularly as shown in Figures 4 and '1 to 12. The crank shaft 6 at its upper end between the keys 29 and 30 is provided with a circular cylindrical portion I56 on which is journaled an assenrbly 151 of cam actuators, sometimes referred to as cam cams. The cam actuators are all of substantially identical shape as shown in Figures 13 to 16 and can occupy any rotary position but primarily occupy four selected positions.

The central portion of the cam actuator assembly I51 is provided with an enlarged ring I56 (Figure 5) having a plurality of depressions I59 at appropriate locations. Engageable with these depressions is a detent ball I6 I movable in a radial hole I62 in the intermediate ring 34 and pressed radially inward by a spring I63 retained by a plug I64. While the cam assembly IE1 is freely rotatable on the crankshaft, it is normally retained in any one of four positions by the detent I6I.

As particularly illustrated in Figures 13 to 16 inclusive, there are shown the various locations of the individual cam actuators in each of the four positions of the cam assembly I51 to produce the correspondingly correct locations for the cam rings IOI, I2I, I36 and I46 respectively. For example as shown in Figure 13 the exhaust cam ring IOI is actuated by a cam I66. When the actuator cam I66 is in one extreme position as shown in Figure 13A, the exhaust cam ring IOI has the reverse position also illustrated in Figure 7. When, as shown in Figure 13B, the actuator cam I66 is advanced one step, approximately through an angle I61; that is, from retention by one of the detent notches I59 to the next detent notch, the cam cam I66 engaging inward projections I68 and I69 on the interior of the cam ring IIlI shifts the cam ring WI from one extreme position to the other. The dimension measured across any diameter of the cam cam is substantially constant. The diametrical distance between the projections I68 and I69 is fixed. The effect of rotation of the actuating cam 166 with respect to the crankshaft 6 is to shift the cam ring IOI from one extreme position into another extreme position or substantially against the bolt 33 by rotation about the bolt 32. The actuating movement therefore shifts the cam ring I6I between its reverse position and its forward position.

As shown in Figure 130, a further increment of rotation of the actuating cam, illustrated by the arrow I'iI, produces no further projecting movement of the cam ring 161 but does serve to hold the cam ring in proper position during the time the engine operates in its 40 per cent cutoff forward condition. Similarly, as shown in Figure 1313, an additional increment of rotation of thecain cam I66 as illustrated by the arrow I112 retains the cam ring I6I in its forward position while the engine is conditioned for 75 per cent forward inlet cutoff".

The positions of the cam ring I2I responsive to the four positions of its actuating cam 113 are illustrated in Figures 14A to D. In the initial positions of the cam I13 (displaced from that of the actuating cam I66) the cam ring i'ti is projected (Figure 14A) but as the actuating cam I13 is rotated through an increment represented by the arrow I14 into the position illustrated in Figure 143, the cam ring I2I is retracted from its previously projected position and is projected on the opposite side. This serves to shift the inlet valve actuation from 15 per cent cutoff during reverse rotation to a 10 per cent cutoff during forward rotation. A further increment of motion of the cam cam I13 as illustrated in Figure and represented by the arrow I16 is effective to hold the cam ring I2I in its 10 per cent cutofi position. Similarly, as shown in Figure 14D, a still further increment of motion represented by the arrow I11 retains the 1 I 36 remains within the circular envelope.

9 cam ring I2I in its 10 per cent cutoff location.

As illustrated in Figures A to D, the cam ring I 36, although provided with an actuating cam I18 of the same shape as those previously described, operates somewhat differently in that it does not project beyond a circular envelope position on one side of the cam assembly 26. The cam ring position during reverse rotation is shown in Figure 15A within the envelope curvature and has no effect. Even when the actuating cam I18 advances through an increment of motion indicated by the arrow I19, the cam ring The cam ring I36 remains in retracted condition during reverse rotation and also during 10 per cent cutoff forward rotation of the engine.

When the cam actuator I18 advances through a further increment illustrated by the arrow I8! in Figure 150', the cam ring I35 is shifted across center so that its surface I39 is effective to produce a 40 per cent duration of opening of the inlet valves. A further increment of motion of the actuating cam I18, illustrated by the arrow I82 in Figure 15D, retains the cam ring I36 in its projected position during the time the engine operates at '75 per cent cutoff forward rotation.

Finally, as shown in Figures 16A to D, the cam ring I99 during reverse rotation is held within a circular envelope by virtue of the actuating cam I93. This is the position shown in Figure 16A. As shown in the Figure 163, during operation of the engine at 10 per cent cutoff forward condition, the cam ring hi6 is held in ineffective position even though the actuating cam I83 has moved through one increment indicated by the arrow I 84. When the actuating cam I83 has moved through another increment as indicated by the arrow I89 in Figure 160, the cam ring I46 is still ineffective. But when the actuating cam I83 has moved through its final increment of movement, as illustrated by the arrow I81 in Figure 16D, the cam ring I46 is then shifted so that its actuating portion I99 projects to hold the-inlet valve motion train open for 75 per cent cutoff.

With this arrangement, the various cam rings operate directly upon the several valve actuators or followers and are positioned in such a way that they are either effective or ineffective to provide the forward and reverse movements and the various positions of cutoff desired.

The relative rotation of the group I51 of cam cams or cam actuators with respect to the crankshaft 9 is effectuated by structure particularly illustrated in Figures 1, 3 and 4. The assembly IE1 is formed with a pair of diametrically opposite axially extending grooves I9! and I92. Designed to operate in the grooves is a cross pin I93 also passing through a pair of helical apertures I 94 and I96 out diametrically opposite each other through the hollow end of the crankshaft. The pin I93 pierces an operating rod I91 coaxial with the crankshaft and movable longitudinally with respect thereto. A thrust bearing I99 in an operating collar I99 is mounted on the end of the operating rod I91.

When the collar I99 is moved up and down in the direction of the crankshaft axis it simultaneously moves the thrust bearing with it. The collar I99 does not revolve with the crankshaft. The operating rod I91 revolves with the crankshaft and is translated with respect thereto. As it travels, it carries the pin I93 axially and rotatably with respect to the crankshaft because of contact with the boundaries of the helical 10 apertures I99 and I96. The rotation of the pin I93 produces a corresponding rotation of the assembly I51 with respect to the crankshaft and moves the various actuating cams with respect to the crankshaft.

Motion is imparted to the shifting collar I99 by a fork 2m bifurcated and notched at its ends to engage stubs 292 and 293. The fork lever 2M, as shown especially in Figure 1, is mounted on a rotatable shifting shaft 294 journaled in a cover 299 secured to the crankcase by fastenings 291. An appropriate mechanism (not illustrated) is utilized to rotate the shaft 294 into any of four selected positions corresponding to the four positions of the detent mechanism shown in Figure 5. By simply moving the shaft 299, in most cases accomplished by an operator controlled hydraulic mechanism, the rod I91 is axially displaced and the actuator cams are revolved into appropriate positions to shift the cams 19L 52L I96, and I 39 into proper positions to produce the requisite operation of the engine.

In an alternative form of the invention disclosed especially in Figures 17 and 18, the engine for the most part is substantially unchanged. In place of the cam assembly 25, a cam drum 2i I is keyed to the upper end of the crankshaft 299 for rotation therewith and is held against axial movement by a jam nut 2 I2. The cam drum 2i I includes .a reverse exhaust cam ZIE, a forward exhaust cam 2%, a reverse inlet cam 2H5, a forward 10 per cent cutoff inlet cam 2 I1, a forward 40 per cent inlet cam 2I3, and a forward 75 per cent cutoff inlet cam 259. These cams, all revolve in unison with the crankshaft.

Encompassing the cam drum 2H are two cam follower rings 22! and 222. These rings are coaxial with the crankshaft 299 and are mounted for rotation in a circular cylindrical cage 223 interrupted at various areas of its periphery. The cage 223 includes a lower inturned flange 224 on which the ring 222 rests and has an upper out-turned flange 225 resting on the crankcase top wall 242. A cover plate 293 is secured by fastenings 2M to the crankcase and incorporates an internal downturned flange 249 resting at intervals on the upper ring 722i to act as a confining means for the rings.

The rings carry cam followers of the plunger type. Since for each cylinder there is an appropriate set of followers, a descri tion of one set applies to the others. As shown particularly in Figure 1'7, the upper cam ring 22! is rotatable between two extreme positions by an operating lever 296 projecting through an aperture 291 in the rear wall of the crankcase 6. A hydraulic actuating mechanism 298 is preferably utilized to move the lever 299 with an arcuate motion designated by the arrow 249 between one extreme position, indicated by the line E and another extreme position indicated by the line F. In the position shown for reverse engine rotation, the ring 22I is so turned that each of four exhaust valve actuating plungers or followers 25I is in appropriate position to operate a shoe 252 on a rocker follower 959 corresponding to the follower 99 as shown in Figure 3. The follower 293 connects with the rocker d6 exact- 1y as shown in Figure 3 and the rest of the motion train is the same as previously described.

In this position of the mechanism, a flat shoe 259 on the inner end of the fcllower 25I is contacted by the revolving reverse exhaust cam M3. The shoe 259 is extended to abut the subjacent shoe which itself abuts the wall of a ll groove 256 turned in the ring 2H and so rotation of the follower 25: is prevented. If the shoe extension is omitted, the follower is free to rotate in its bore in the ring fit. The outer end of the follower 25! is turned or provided with adouble bevel 25?. In any radial position of the parts, upon rotation of the ring 22! and the follower 25! (Figure 17) can move between one extreme position (shown by the line 2553) out of contact with the shoe 252 and another extreme position (shown by the line 259) in contact with the shoe. When the plunger 25! is out of contact with the shoe, the cam 2 I 3 is ineffective upon the follower 253, but when the plunger 225i is in its active position, the cam 253 is efiective to produce corresponding motion of the follower 253. All of the valve operating mechanisms are similarly actuated and disposed. The reaction of the valve actuating mechanisms against the ring 22! which might tend to displace the ring from either of its extreme positions is appropriately resisted by the hydraulic shift mecha-- nism 248. Any sort of retainer or look which will hold the lever M55 in either extreme position when desired is effective for the purpose.

At the time the reverse exhaust follower 25! is shifted out of contact with the shoe 252, a forward exhaust follower 25!, previously located in ineifective position as shown in Figure 17, is moved into active position. The cam 2 Hi rather than the cam 2 i3 then is effective to control the exhaust valve events. Which cam, fit or tilt, is effective depends upon the position of the lever 245. The exhaust function of all cylinders for forward and reverse rotation is so controlled.

Since with a change in the exhaust function it is necessary also to effectuate a change in the inlet function, the ring 225 also carries a pair of inlet followers 262 and 2&3 or plungers similar to and spaced immediately below their corresponding exhaust followers. One of the inlet followers is actuated by the reverse inlet cam 2 I and the other inlet follower is actuated by the forward 10 per cent cutoff cam 2 ll. Thus when the ring 22! is shifted between forward and reverse position, the inlet followers 262 and ass are similarly shifted and are individually made active or effective upon an elongated shoe 26 3 on a follower lever 2G5 substantially identical with the inlet follower lever I5 as shown in Figure 4. The follower 268 connects with the inlet rocker Bi as before and the remaining part of the inlet valve motion train remains exactly the same. Conse quently, when the ring 221 is shifted, both the exhaust and the inlet events are changed by cutting into or out of effect the respective cams 2 i3 and 2H5 for reverse motion and 2M and 25'? for forward motion at per cent cutoff.

Since ten per cent cutoff inlet cam 21? is 2.1- ways effective or may be left in effective position in the 40 per cent and '75 per cent forward cutoffs, there is provided a duplicate shift mechanism 266 effective upon a lever 25? like the lever 24% and connected to the ring 222. Preferably, the lever 261 swings from one extreme position 268 (Figure 17) to another extreme position 26%. and may also be retained in a neutral or central position 2' by the shifting mechanism The ring 222 carries a pair of followers 2'52 and 213 like the other plunger followers in the set and disposed to bear on the forward 40 per cent cutoff cam 2 l 8 and the forward '55 per cent cutoff cam 2l9 respectively.

When it is desired to operate in forward 10 per cent cutoff with the cam ill effective upon the follower 263, the lever 25'! is left in its central or neutral position 2H. When a forward 40 per cent cutoff is desired, the lever 26? is actuated to revolve the ring 222 into an extreme position to bring the various followers 2'52 bearing on the cam 2 [8 into contact also with the shoe 26 3. Under these circumstances, both the cams M6 and EH; through their followers 282 and 212 are effective simultaneously to give an opening impulse to the shoe 25d and although the cam follower 263 may retract with the cam 211, the follower 272 remains projected until the cam 218 permits it to withdraw at the 40 per cent cutoff position.

Similarly, when a forward 75 per cent cutoff is I desired, the lever 26'! is actuated to its opposite extreme position bringing the followers 213 into effect upon the shoe 2%. Under these circumstances, the follower 263 operates as before in connection with the follower 2'53 to effectuate the opening movement of the valve. Although the follower 263 may withdraw at the forward 10 per cent cutoff position, the follower 213 cannot withdraw until the forward 75 per cent cutoff position, at which time the shoe 26% returns to its previous location and permits the valves to close. With this alternative mechanism, the same events are obtained as are obtained with the previously described structure.

In the alternative form particularly, the lubrication is improved by the provision of a supply of oil through a lubricating oil pressure tube 216 anchored in the cover 253. A tube 217 held in the hollow end of the crankshaft 239 to rotate therewith by the jam nut 212 and a pin 278 communicates through a seal ring 2?!) with the tube 216. Some oil under pressure passes through the interior bore 28.! of the crankshaft while some digresses through ports 282 to holes 283 extending through the cam drum 2 l I. At its lower end the ring 222 is close to the cam hub and permits only slight oil leakage. Oil discharged from the holes 283 is retained by the rings 22! and 222 except for some that leaks out between the rings and around the various plungers. The remaining oil overflows the top ring 22! and passes through notches 284 in vertical registry with the plungers contacting the various follower shoes. A cascade of oil thus falls over these part and finally drains into the engine crankcase for reuse. Some oil is also distributed by the motion of the parts so that good lubrication is continuously provided.

What is claimed is:

1. A steam engine with cam actuated valves comprising a crankcase, cylinders. in line on said crankcase, pistons in said cylinders, a crankshaft in said crankcase arranged with the rotational axis of said crankshaft paralled to said line, means connecting said pistons and said crankshaft, valves in said cylinders for controlling steam flow, cams on said crankshaft, bell cranks in said crankcase, push rods arranged approximately parallel to said axis and disposed between said cams and said bell cranks, motion transmitting means between said cams and said push rods, and thrust rods between said bell cranks and said valves.

2. A steam engine with cam actuated valves. comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a plurality of cylinders arranged on said crankcase in alignment axially of said crankshaft, pistons in said cylinders, means connecting said pistons and said crankshaft, a plurality of valves in each of said cylinders for controlling steam flow, a plurality of cams on said crankshaft adjacent one end thereof, bell cranks in said crankcase, push rods extending approximately parallel to the rotational axis of said crankshaft and arranged between said cams and said bell cranks, motion transmitting means between each of said cams and certain of said push rods, and thrust rods extending approximately perpendicular to the rotational axis of said crankshaft between at least some of said bell cranks and said valves.

3. A steam engine with cam actuated valves: comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a cylinder mounted on said crankcase with the axis of said cylinder perpendicular to the axis of said crankshaft, a piston in said cylinder, means connecting said piston and said crankshaft, valves in said cylinder for controlling steam fiow, bell cranks in said crankcase for actuating said valves, cams on said crankshaft adjacent one end thereof, push rods extending approximately parallel to the axis of said crankshaft between said cams and said bell cranks, and means for transmitting motion between said cams and said push rods.

4. A steam engine with cam actuated valves comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a cylinder mounted on said crankcase with the axis of said cylinder perpendicular to the axis of said crankshaft, a piston in said cylinder, means connecting said piston and said crankshaft, valves. in said cylinder movable in a direction perpendicular to the axis of said crankshaft for controlling steam flow, bell cranks for actuating said valves, cams on said crankshaft, followers actuated by said cams, and push rods approximately parallel to the axis of said crankshaft arranged to transmit motion between said followers and said bell cranks.

5. A steam engine with cam actuated valves comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a cylinder on said crankcase, a piston in said cylinder, means connecting said piston and said crankshaft, valves in said cylinder movable in a direction perpendicular to the axis of said crankshaft for controlling steam flow, bell cranks for actuating said valves, cams on said crankshaft,

followers rotatable about axes parallel to the axis of said crankshaft and actuated by said cams, rockers rotatable about axes in planes perpendicular to said crankshaft and engaging said followers, andpush rods approximately parallel to the axis of said crankshaft in motion transmitting relationship between said rockers and said bell cranks.

6. A steam engine with cam actuated valves comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a cylinder on said crankcase, a piston in said cylinder, means connecting said piston and saidcrankshaft, a stub shaft in said crankcase, a pair of bell cranks on said stub shaft, a first steam controlling valve in said cylinder movable in a direction perpendicular to the axis of said crankshaft and engaging one of said bell cranks, a second steam controlling valve in said cylinder movable in a direction perpendicular to the axis of said crankshaft, a rocker lever on said cylinder and engaging said second valve, a thrust rod extending between said rocker lever and the other of said bell cranks, a pair of cams on said crankshaft adjacent one end thereof, followers rotatable about axes parallel to the axis of said crankshaft and actuated by said cams, rockers rotatable about axes in planes perpendicular to said crankshaft and engaging said followers, and push rods approximately parallel to the axis of said crankshaft in motion transmitting relationship between said rockers and said bell cranks.

'7. A steam engine with cam actuated valves comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a cylinder on said crankcase, a piston in said cylinder, means/connecting said piston and said crankshaft, valves in said cylinder for controlling steam flow, cam followers movable in planes perpendicular to said axis, means for connecting each of said cam followers to actuate an associated one of said valves, a plurality of axially spaced and axially fixed cams on said crankshaft, and means rotatable about the axis of said crankshaft for actuating said cam followers with alternatively selected ones of said cams.

8. .A steam engine with cam actuated valves comprising a crankcase, a crankshaft mounted in said crankcase for rotation about an axis, a cylinder on said crankcase, a piston in said cylinder, means connecting said piston and said crankshaft, valves in said cylinder for controlling steam flow, a plurality of axially spaced and axially fixed cams on said crankshaft, axially fixed cam followers of substantially the same axial extent as said plurality of cams, means rotatable about the axis of said crankshaft for making selected ones of said cams effective upon said followers, and means for transmitting motion of said followers to said valves.

9. In a steam engine with cam actuated valves, a plurality of cams arranged side by side along an axis and rotatable about said axis, means for holding said cams against shifting movement along said axis, a follower mounted to move in a direction having a component perpendicular to said axis, said follower being of substantially the same axial extent as said plurality of cams, and means rotatable about said axis for selectively making individual ones of said cams effective upon said follower.

10. In a steam engine with cam actuated valves, a plurality of cams arranged side by side along a first axis and rotatable about said first axis, means for holding said cams against shifting along said first axis, a cam follower of substantially the same axial extent as said plurality of cams, means mounting said cam follower to rock about a second axis parallel to said first axis, and means rotatable about said first axis for making selected ones of said cams effective upon said follower and simultaneously making other ones of said cams ineffective upon said follower.

11. In a steam engine with cam actuated valves, a plurality of cams arranged side by side along an axis, means mounting said cams for rotation about said axis, means for holding saidcams against shifting along said axis, a cam follower having a portion overlying all of said plurality of cams, means mounting said cam follower for motion having a component perpendicular to said axis, means for holding said follower against shifting along said axis, means rotatable about said axis effective in different rotated positions thereof for rendering d fferent selected ones of said cams effective upon said portion of said follower, and means for holding said rotatable means against shifting along said axis.

12. In a steam engine with cam actuated valves, a plurality of cams arranged side by side along an axis, means mounting said cams for rotation about said axis and supporting said cams for shifting crosswise of said axis, means for holding said cams against shifting along said axis, a cam follower having a portion overlying all of said plurality of cams, means mounting said cam follower for motion having a component perpendicular to said axis, means for holding said follower against shifting along said axis, means rotatable about said axis effective in different rotated positions thereof for shifting different selected ones of said cams crosswise of said axis to be effective upon said portion of said follower, and means for holding said rotatable means against shifting along said axis.

13. In a steam engine with cam actuated valves, a plurality of cams arranged side by side along an axis, means mounting said cams for rotation about said axis, means for holding said cams against shifting along said axis, a cam follower having a portion overlying all of said plurality of cams, means mounting said cam follower for motion having a component perpendicular to said axis, means for holding said follower against shifting along said axis, a ring interposed between said cams and said portion of said follower, means mounting said ring for rotation about said axis, means for holding said ring against shifting along said axis, a plurality of tap-pets mounted in said ring in difierent axial and. circumferential locations, and means for rotating said ring to interpose different ones of said tappets between different ones of said cams and said portion of said follower.

14. In a steam engine with cam actuated valves,

a plurality of forward and reverse cams arranged side by side along an axis, means mounting said cams for rotation in unison about said axis, means for holding said. cams against shifting along said axis, a cam follower having a portion overlying all of said forward and reverse cams, means mounting said cam follower for motion having a component perpendicular to said axis, means for holding said follower against shifting along said axis, a pair of rings interposed between said cams and said portion of said follower, means mounting said rings for rotation about said. axis, means for holding said rings against shifting along said axis, a plurality of tappets mounted in said rings in different axial and circumferential locations, and means for rotating said rings individually to interpose different ones of said tappets between said forward and reverse cams and said portion of said follower.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 995,384 Stanley June 13, 1911 1,943,118 Holmes Jan. 9, 1934 2,009,745 Riesner July 30, 1935 2,020,923 Von Seggern Nov. 12, 1935 2,513,932 Williams July 4, 1950 2,528,627 Whiting Nov. '7, 1950 FOREIGN PATENTS Number Country Date 162,752 Germany Sept. 14, 1905 

